Glass is heated for a variety of purposes. These purposes include, among other things, bending or tempering individual heated glass sheets. Typically, glass is heated to some desired temperature through the use of electrical or gas heaters. Such heaters may be exterior or interior to the processing apparatus.
One particularly good method for providing a heated chamber atmosphere is disclosed in U.S. Pat. No. 4,222,763 (hereinafter '763 patent). This patent is incorporated by reference herein. The '763 patent discloses the use of a compressor or pump to supply compressed air to a heat exchanger which heats the air supplied to it, and distributes it to the glass treating apparatus.
The '763 patent also discloses the use of gas jet pumps for producing a secondary flow of heated gas from the primary flow of heated gas provided by the compressor and heat exchanger. The use of heated pressurized air directed at the glass sheet, as shown in the '763 patent, encourages heat transfer between the chamber atmosphere to the glass sheet.
In practice, however, the structure described in the '763 patent necessitates maintenance on both the compressor and the heat exchanger. Additionally, the compressor cannot practicably be located downstream from the heat exchanger as heated air causes additional wear upon pump parts. Additional maintenance in systems disclosed in the prior art arises from the need for maintenance of the conveyor system used in prior systems such as the one disclosed in the '763 patent to convey the glass sheet through the glass treating apparatus.